Outstanding strength-ductility balance in a Ti–N alloy by tuning ball milling time

The trade-off between strength and ductility is a prevalent issue in strengthening commercially pure titanium (CP–Ti). This study presents a method to prepare ultra-high strength Ti–N alloys with adequate ductility using ball-milling (BM) and spark plasma sintering (SPS) techniques, based on nitrogen solid solution and grain refinement strengthening. The effect of ball milling time of mixed powders on mechanical properties of Ti–N alloys was studied systematically. Quantitative analysis reveals that solid solution strengthening and grain refinement strengthening worked synergistically to enhance yield strength of alloys. The Ti–N alloys with the most favorable mechanical properties demonstrated a yield strength of 1606 MPa and a compressive plastic strain of 14.44 %. The development of novel Ti–N alloys provides a viable strategy for the advancement of high-performance titanium alloys using ubiquitous elements.